To reduce air pollution from airborne dust, cf. R. W. Shaw, "Air Pollution by Particles", Scientific American, 257:96-103 (August 1987), in many environments which contain or are in the vicinity of loose aggregate material, e.g. mining and industrial locations which produce or use coke, coal, sand or other loose aggregate material, one must provide means for preventing dust particles from accumulating in the surrounding environment. For example, in coal mines it is often mandatory to provide means for preventing accumulations of coal dust from remaining suspended in the air.
Various dust suppressant compositions and methods are known in the art for spraying in air to reduce airborne dust or for spraying on substances which develop dust, for example coal aggregates. U.S. Pat. No. 4,369,121 (Callahan et al) discloses a composition for controlling dust which comprises a cellulose ether and a wetting agent such as an ethylene oxide condensate of nonyl- or octylphenol, ethylene oxide condensates of straight chain alcohol, fatty acid amides, quaternary ammonium compounds, organic phosphate esters, and sulfonic acids. U.S. Pat. No. 4,169,170 (Doeksen) discloses a composition and method for controlling dust during coal transportation wherein the composition comprises an aqueous solution containing an asphalt emulsion or a black liquor lignin product and a water soluble ethoxylated alkyl phenol. U.S. Pat. No. 4,425,252 (Cargle et al) discloses an aqueous coal dust abatement composition including a water soluble sulfonic acid salt and ethoxylated nonyl phenol and U.S. Pat. No. 4,428,984 (Shimizu et al) discloses a method of preventing dusts by spreading an aqueous solution including an ethoxylated alkyl phenol, alcohol, fatty acid, amine or fatty acid amide and a polyhydric alcohol.
U.S. Pat. No. 4,487,615 (Taylor et al) discloses a method of reducing mine dust by spraying water including a surfactant produced by reacting ethylene oxide with linear primary alcohols. U.S. Pat. Nos. 4,136,050 (Brehm) and 4,171,276 (Brehm) disclose a dust suppression composition comprising an aqueous solution of alkylphenoxy polyethoxy ethanol and a copolymer of ethylene oxide and propylene oxide.
U.S. Pat. No. 4,737,305 (Dohner) disclose a dust suppressant composition comprising an aqueous solution of a dust suppressant comprising an ethoxylated alcohol and an ethoxylated alkyl phenol. The patent also discloses methods of suppressing dust by spraying such compositions in dusty air or applying the composition to a dust generating substance.
However, the above dust suppressing compositions and methods all have various disadvantages in that the compositions are not immediately effective (and require an extended time for satisfactory performance) and/or are not sufficiently persistent in suppressing dust or that the compositions include excessive aromatic or other less biodegradable or toxic materials. There is therefore a need for an efficient dust suppressant composition which enhances the settling and/or suppresses the generation of air-borne dust and which is substantially biodegradable and nontoxic in the environment.